Fix for leftover COFF debugging symbols

[Nick Clifton]

Hi Mark,

: 2000-07-16  Mark Elbrecht  <snowball3@bigfoot.com>
: 
: 	* config/obj-coff.c (obj_frob_symbol): Don't merge labels. Don't merge
: 	  if the symbol isn't constant. Don't call S_SET_EXTERNAL if the
: 	  storage class is already set.

Approved.

Cheers
	Nick

PS.  Thanks for tracking this one down!